* Fix#2434
* Treat holes as unkeyed, normalize boolean/null/undefined
This brings a lot better consistency with that API, even though it's
slightly breaking. (I had to update a bunch of tests to correspond with
it.)
* Fill in PR number [skip ci]
The previous example about hiding keys had syntax errors, and example in itself didn't follow our own guidelines (key should be on immediate child of an array)
In the new example we reuse the code from the previous example but break out a User component (which is much more likely) and the example says to move the key from inside the user component instead
